Method and apparatus for orienting drill stems



G. A. SMITH Filed May 4, 1 959 Jan. 16, 1940.

METHOD AND APPARATUS FOR ORIENTING DRILL STEMS m .1% .A y 4W 1 m 0 00, M52 mfl wm 7 1 7 \W W TQMMLM WIT/V585:

Patented Jan. 16, 1940 UNITED STATES METHOD AND APPARATUS FOR. ORIENTINGDRILL STEMS George A. Smith, Philadelphia, Pa., assignor to Sperry-SunWell Surveying Company, Philadelphia, Pa., a corporation of DelawareApplication May 4, 1939, Serial No. 271,743

8 Claims.

This invention relates to a method and apparatus for orienting drillstems, and, more specifically, to a method of directional drilling whichhas as part of its procedure the orientation of a drill stem.

The orientation of the lower portions of drill stems within bore holesis important for various purposes. For example, in setting of whipstocksor directional drilling tools the whipstock or other tool is loweredinto the bore hole in an arbitrary position or perhaps with an attemptto get it in a predetermined position by so-called drill stemorientation. Orientation by the latter method is never absolutelycertain because of the possibility that in lining up the drill stemlengths there may have occurred accumulation of errors which wouldresult in substantial deviation of the tool from the assumed position.Accordingly, in either case it is desirable to check the orientation ofthe lowermost portion of the drill stem by means of a well surveyinginstrument. This may be ac complished in various fashions, for example,the inside of the lowermost portion of the drill stem may be providedwith a key, adapted to engage a groove in awell surveying instrument, orvice versa, with the result that when the well surveying instrument islowered within the drill stem it will be brought into a predeterminedrelationship with the stem. Alternatively, mechanical complications maybe avoided by the use of the method and apparatus describedin HyerPatent 2,120,670, dated June 14, 1938.

In my prior application Serial No. 236,996, filed October26, 1938, thereis described another alternative method which avoids even the presenceof a magnetic element in the drill stem, but utilizes a well surveyinginstrument which is adapted to give indications of its orientation withrespect to the earth.

The present invention provides an improved -method and apparatus fororienting the lower portion of a drill stem for any of the variouspurposes for which such orientation is usually practiced. Specifically,it avoids the presence of any magnetic or keying-elements within thedrill stem and doesnot require either precautions or specialconstruction to permit a magnetic compass to respond to the field of theearth. It will become apparent in the following description that theapproved method and apparatus is adapted for the general purposesdescribed in my prior application mentioned above. I

The various objects of the invention will become apparent from thefollowing description,

, sampling or the like.

read in conjunction with the accompanying drawing, in which:

Figure 1 is a diagrammatic sectional view of the lower portion of adrill stem together with a well surveying instrument cooperatingtherewith to indicate the orientation of the portion of the drill stemwhich is illustrated; and

Figure 2 is a perspective diagram illustrating the matters which must betaken into account in determining the orientation of the drill stem.

Referring first to Figure 1, there is illustrated diagrammaticallytherein the lower portion of a d'rill stem comprising at 2 a sub forminga portion of the drill stem and adapted to receive and position inpredetermined fashion a well surveying instrument. Below this andconnected through it the tubular member 4 maybe a. bit indicated t 6.Connected to this assembly y a rivet It or the like, which may bereadily sheared off, is a wdripst ck 8. The whipstock and drilling toolare illustr ted merely as examples,

since it will be evident that the invention is applicable to theorientation of a' drill stem for any of many purposes and in connectionwith the use of various tools, for example, for, purposes of directionaldrilling, oriented coring, side wall It will be evident that directionaldrilling may be accomplished through the use of 'a' bent drill stem asdescribed in my prior application and in Ragland Patent 2,114,476, datedApril 19, 1938.

In the vicinity of the portion of the drill stem which is 'to beoriented, a sub such as indicated at 2 may be provided with an enlargedbore indicated at l2 communicating with a socket bore l4 making apredetermined angle with the axis. of the bore hole and adapted to alignat such angle a well surveying instrument such as indicated at 20.Reference 'is here made to the arrangement of the socket H. at apredetermined angle relative to the bore hole. If the drill stem isstraight this angle is, of course, the same as the angle of the socketwith respect to the axis of the drill stem. Such would not be the case,however, if there was used a bent drill stem as disclosed in the Raglandpatent.

In the assembly of the device the socket H has an angular position inthe drill stem assembly which is predetermined relative to the toolorother element carried by the drill stem. For simplicity it will beassumed in the following description that the socket inclines downwardlytoward the direction in which a whipstock 8 faces. Any predeterminedrelationship is, of course, equally usable.

' at all times, it is preferable to bypass the socket I4 and bore It byone or more grooves indicated at l8 which, as will be evident, willpermit seating of a surveying instrument without interruption of thecirculation of mud.

The surveying instrument 2!) which is adapted to be lowered and raisedby means of a wire line 22, or lowered or raised in any other suitablefashion, for example, by the use of catchers, comprises a pivotedmagnetic compass 24, having contrastingly marked or shaped poles,immediately above which there is located a transparent level 26 or othersuitable means such as a pendulum for indicating inclination withrespect to the vertical. A record of the inclination indicating meansand the compass 24 may be made photographically by projection bylenssystem 28 upon a sensitized member 30, illumination being provided bylamps 32, which are lighted at the proper time under control ofclockwork mechanism. Such instruments for photographic recording arewell known, and the operation need not be described in greater detail.

At the lower end of the well surveying instrument there is provided aspherical socket member indicated at 34 adapted to receive the sphericalhead 36 of a plunger 38 adapted to closely fit the bore l6. Within thishead there is pivoted a powerful magnet 40 which is weighted at one endso that that end will occupy the lowermost position whenever the member38 is tilted from the vertical. The well surveying instrument isenclosed in a, casing of non-magnetic type at least at its lowermostportion designed to withstand the pressures encountered in the borehole. The chamber in the spherical head 38 is also closed to prevent theentrance of mud to the pivoted magnet 40. While the elements in thevicinity of the magnet and compass should be non-magnetic, the sub 2 maybe made of steel if desired. The only requirement is that the magnet 40and compass 24 be sufficiently close together that the compass willalign itself with the magnet and that magnetic materials be suflicientlyremote from these elements to prevent any misaligning.

In the operation of the method, assume that the assembly just describedis located in a portion of a bore hole of which the inclination anddirection of inclination is known. The well surveying instrument islowered within the drill stem to a position within the socket l4 andwith the member 38 in the bore IS. The azimuthal position of theinstrument may be quite arbitrary and the universal connection affordedby the ball and socket joint will permit the attainment of the positionjust described. Through the usual timing means a photographic record isthen made. This record will show the inclination of the surveyinginstrument with respect to the vertical and the position of the compass24 with respect to the direction of deviation of the bubble. The compass24 will be in the direction of maximum inclination of the bore hole withrespect to the vertical inasmuch as the weighted end of the magnet 40will lie in lowermost position. The Well surveying instrument is thenremoved from the hole, the record developed and calculations made.

The calculations and significance of the records made will be bestappreciated by considering Figure 2. At OM there is indicated thevertical direction, north being indicated by the arrow N. 01? is thedirection of the bore hole determined from a previous survey.

The angle of inclination of the socket l4 with respect to the axis ofthe bore hole is known, and consequently it will be known that the wellsurveying instrument must lie in the direction of one of the straightline elements of a cone having a vertex angle twice the inclination ofthe angle of deviation of the socket from the axis of the bore hole. Theintersection of such a cone with the horizontal plane is indicated bythe ellipse Q.

The record of the inclination indicating member'such as the level 26will show the inclination of the well surveying instrument with respectto the vertical. Assume this angle to be b, the angle of the bore holewith respect to the vertical being a. Then it will be known that thedirection taken by the well surveying instrument will be 0U or OV which,on the diagram are lines forming the angle b with the vertical andpassing from 0 through points on the ellipse Q.

With this information only, an indeterminateness would result. If thewhipstock or other tool was aligned angularly as assumed with respect tothe direction of slope of the well surveying instrument it might face ineither the direction Y or the direction Y.

The record of the position of the compass 24, however, will solve thisindefiniteness. The compass 24 will indicate the direction PM, i. e.,the plane in which the bore hole slopes or, in other words, at points Uand V the directions UT and VT. The bubble or other inclinationindicating means will indicate the direction UM or W indicated by thelines S and S respectively. It will be evident, therefore, that the sideof the bubble on which the compass lies will indicate whether the pointD or the point V represents the point indicative of the direction ofslope of the well surveying instrument. It will be noted that the lineUM is clockwise with respect to UT, while the line VM iscounter-clockwise'with respect to VT. From the relationship of thebubble to the compass, therefore, it will be apparent whether Y or Y isthe direction of orientation of the whipstock or other tool.

While the magnet 40 which indicates the direction of slope of the borehole may be lowered with the instrument as part thereof as indicated inFigure 1, it will be evident that this compass may be permanentlysecured at the bottom of the socket l4 within the drill stem with itsaxis parallel to the axis of the bore hole, so that when the instrumentis located in the socket its compass will be forced to align itself withthe magnet which will indicate the direction of slope of the hole.

It will be evident that various modifications of the invention may bemade within its scope.

What I claim and desire to protect by Letters Patent is:

1. The method of determining the orientation of a portion of a drillstem within a bore hole comprising determining the slope of a bore hole.at the location where such determination is to be made, lowering intothe bore hole a hollow drill stem which, at the, portion which ispositioned at the location where such determination is to be made, isarranged to position a well surveying instrument at a known angle ofdeviation from the axis of the hole, causing to be made by an instrumentso positioned a record of the inclination of the instrument with respectto the vertical and of the relationshipof said inclination to thedirection of inclination of the bore hole with respect to the vertical,and removing the instrument from the drill stem.

2. The method of determining the orientation of a portion of a drillstem within a bore hole comprising determining the slope and directionof slope of a bore hole at the location where such determination is tobe made, lowering into the,

bore hole a hollow drill stem which, at the portion which is positionedat the location where such determination is to be made, is arranged toposition a well surveying instrument at a known angle of deviation fromthe axis of the hole, causing to be made by an instrument .so positioneda record of the inclination of the instrument with respect to thevertical and of the relationship of said inclination to the direction ofinclination of the bore hole with respect to the vertical, and removingthe instrument from the drill stem.

3. The method of determining the orientation of a portion of a drillstem within a bore hole comprising determining the slope of a bore holeat the location where such determination is to be made, lowering intothe bore hole a hollow drillstem which, at the portion which ispositioned at the location where such determination is to. be made, isarranged toposition a well surveying instrument at a known angle ofdeviation from the axis of the hole, and is provided with means definingthe direction of the axis ofthe hole, causing to be made by aninstrument s0 positioned a record of the inclination of the instrumentwith respect to the vertical and of the relationship of said inclinationto the direction of inclination of the bore hole with respect to thevertical, and removing the instrument from the drill stem.

4. The method of determining the orientation of a portion of a drillstem within a bore hole comprising determining the slope and directionof slope of a bore hole at the location where such determination is tobe made, lowering into the bore hole a hollow drill stem which, at theportion which is positioned at the location where such determination isto be made, is arranged to position a well surveying instrument at aknown angle ofdeviation from the axis of the hole, and is provided withmeans defining the direction of the axis of the hole, causing to be madeby an instrument so positioned a record of the inclination of theinstrument with respect to the vertical and of the relationship of saidinclination to the direction of inclination of the bore hole withrespect to the vertical, and removing the instrument from the drillstem.

5. Means for determining the orientation of a portion of a drill stemwithin a bore hole comprising means in the drill stem for positioning awell surveying instrument at a known angle of deviation from the axis ofthe hole at the location where such determination is to be made, and awell surveying instrument arranged tobe s0 positioned and provided withmeans to make a record of the inclination of the instrument with respectto the vertical and of the relationship of said inclination to thedirection of inclination of the bore hole with respect to the vertical.

6. Means for determining the orientation of a portion of a drill stemwithin a bore hole comprising means in the drill stem for positioning awell surveying instrument at a known angle of deviation from the axis ofthe hole at the location where 'such determination is to be made, and awell surveying instrument arranged to be so positioned and provided withmeans to make a record of the inclination of the instrument with respectto the vertical and of the relationship of said inclination to thedirection of inclination of the bore hole with respectto the vertical,said last means comprising a device cooperating with means in the drillstem defining the direction of the axis of the hole.

7. Means for determining the orientation of a portion of a drill stemwithin a bore hole comprising means in the drill stem for positioning awell surveying instrument at a known angleoi deviation from the axis ofthehole at the location where such determination is to be made, and awell surveying instrument arranged to be so positioned and provided withmeans to make a record of the inclination of the instrument with respectto the vertical and of the relationship of said inclination to thevertical, said last means comprising a magnetic compass arranged torespond to a magnetic element arranged to define the direction ofinclination of the bore hole with respect to the vertical.

8. Means for determining the orientation of a portion or a drill stemwithin a bore hole comprising means in the drill stemior positioning awell surveying instrument at a known angle of deviation from the axis ofthe hole at the location where such determination is to be made, andawell surveying instrument arranged to be so sitioned and provided withmeans to make 8. record of the inclination of the instrument withrespect to the vertical and of the relationship of said inclination tothe direction of inclination of the bore hole with respect to thevertical, said last means comprising a magnetic compass and a magneticelement arranged to define the direction of inclination of the bore holewith respect to the vertical.

GEORGE A. SMITH.

